Field of the Invention
The present invention relates to a vehicle control apparatus aimed at enhancing fuel economy of a vehicle.
Description of the Background Art
Recently, a technique is being developed as a measure taken to enhance fuel economy of an engine-equipped vehicle, according to which coasting is performed by disconnecting a clutch disposed between the engine and drive wheels while the vehicle is moving, so that fuel economy is enhanced by lessening engine drag.
Under the coasting control as above, fuel economy is enhanced by securing a longest possible coasting time. Hence, enhancement of fuel economy depends on determination conditions under which to perform the coasting.
For example, Patent Document 1 discloses that a determination is made so as to select control under which less fuel is consumed depending on whether the coasting control is performed or not when a vehicle is run in a predetermined speed range.
Also, Patent Document 2 discloses that whether or not to perform the coasting is determined while securing a distance long enough to stop the vehicle safely according an inter-vehicle distance and a relative speed with respect to a vehicle in front.
[Patent Document 1] JP-A-2011-183963
[Patent Document 2] JP-A-2012-214181
According to Patent Document 1, however, when the control is switched back from the coasting control, it is necessary to start the engine. Nevertheless, power consumed by a starter used at the engine start is not taken into consideration in this system. Therefore, an effort can still be made for further enhancement of fuel economy.
Also, according to Patent Document 2, a predetermined time is necessary to connect the clutch by starting the engine when the control is switched back from the coasting control. Hence, because it can by no means be said that engine braking is used to secure a braking force, performing the coasting control according to an inter-vehicle distance is meaningless. Therefore, a more effort can be made for enhancement of fuel economy.